The military denied the report. It said the Liberation Tigers of Tamil Eelam (LTTE) may have set off explosions near the hospital.
Sri Lanka has disregarded heavy Western pressure to call a truce to protect tens of thousands of civilians trapped by the LTTE in the war zone, a 5-square km (2-sq mile) strip of coast.
It is difficult to get a clear picture from the war zone, which is generally off-limits to outsiders.
Pro-rebel www.TamilNet.com said two shells killed 64 people and wounded 87 at the field hospital in Mullivaikal, in the south of the LTTE area. Troops are advancing from the north.
Military spokesman Brigadier Udaya Nanayakkara said troops were respecting President Mahinda Rajapaksa’s order from Monday not to use heavy weapons, air strikes or artillery.
The LTTE insists people are staying in the area by choice, despite an exodus of 115,000 to government areas in the last two weeks.
The rebels have vowed not to surrender in their fight for a separate state for Sri Lanka’s Tamil minority. The government has refused to call a truce because it says the LTTE has spurned two this year already and would use a ceasefire to rearm.
The military dropped leaflets Friday with a message from Rajapaksa urging people to leave and promising them safety in government-held areas.
Troops faced eight suicide attacks over the last two days and two loud explosions were heard near the area of the hospital late Friday, Nanayakkara said.
“It may be that something happened accidentally, or they may have done it purposefully to gain propaganda mileage from accusing the government,” he said.
The government routinely accuses the LTTE of creating a humanitarian crisis to build diplomatic pressure for a ceasefire. The LTTE in turn accuses the government of killing civilians.
